This invention relates to a resistance welding control, and more particularly to an apparatus for use with such a welding control which provides a menu and conversation type interface on frame-by-frame basis of visual presentation, making it possible for a one unit to handle a large number of welding schedules.
A resistance welding control generally includes a panel for the purpose of setting welding conditions, indicating measured values of welding properties, and giving predetermined warnings.
FIG. 12 shows a front panel of a resistance control in the prior art. Digital switches in the form of thumwheel switches 200A through 200D are provided to set and indicate welding conditions such as squeeze time (SQUEEZE), first welding current time (WELD 1), cool time (COOL), second welding current time (WELD 2), hold time (HOLD), first welding current value (CURR 1), second welding current value (CURR 2) and the like. Lamps 202 through 208 are used to indicate welding stages and warnings. Current range changeover switches, reset switches and other switches are designated by reference numerals 210 through 216. The illustrated front panel can set and indicate two different welding schedules (SOL A and SOL B) at a time.
In U.S. Pat. No. 4,301,351 to James K. Mathews issued on Nov. 17, 1981, there is a disclosed a similar front control panel with thumwheel switches in which only one welding schedule can be set at a time.
FIG. 13 shows a front panel of a resistance welding control in another prior art. This is of a key input type. Data of welding conditions are input and set by means of a ten key type keyboard 300, and are displayed by means of a seven-segment display 302. Respective setting conditions such as squeeze and first welding times are visually presented by numeric addresses. For example, ADDRESS "31" is shown to represent a first welding current time. The list of such addresses is printed on a manual "ADDRESS TABLE", as shown in FIG. 14. By referring to this address table, an operator enters numeric values for setting conditions and interprets what is displayed.
The above mentioned two type resistance welding controls have respective disadvantages as follows.
While the resistance welding control in FIG. 12 has a front panel from which an operator can understand the whole welding conditions and situations at a glance, the number of welding schedules which can be set at a time with this arrangement is limited to two at most, as indicated in FIG. 12. Accordingly, in a resistance welding process or the like by means of, for example, a welding robot for successively executing a series of welding schedules set therein at intervals (which are too short for an operator to operate digital switches for setting), a single type resistance welding control is unable to keep up with the speed and a large number of such welding control are needed with the consequence of increase in cost and space.
With the resistance welding control in FIG. 13, some welding conditions are presented in the form of numeric addresses so that an operator finds it difficult to understand what is meant thereby. Referring to ADDRESS TABLE (FIG. 14) is troublesome. Even those who are familiar with the address indication would often misread the information.